A good trout or saltwater fly reel will cost between $250 and $400, with replacement spools accounting for as much as half of the cost. When a different type or weight line is wanted, as can happen many times during a single fishing outing, there is presently no alternative but to replace the spool in the fly reel. Thus an avid fisherman has to buy, and then carry, as much as one spool for every kind and weight of line he or she intends to fish with on that day. Conventional replaceable spools incorporate the bearings and bearing surfaces into the spool itself, and the fit of the spool to the reel is therefore critical, both factors tending to drive up the cost of a replacement spool. Even if different lines will not be needed on a particular day, the fisherman will still usually want to fish somewhere different on the next occasion, and will have to replace the spool for the next outing. What is needed is a low cost, tolerant replaceable spool, preferably having no bearings or bearing surfaces of its own. Present mechanisms such as that disclosed by Yeh in U.S. Pat. No. 4,811,916, the text of which is herewith incorporated by this reference, do not fully address these needs.
In addition, conventional fly reels employ a so called static drag mechanism that actually discourages savvy fishermen from fully using it, since a sudden strike or rush of the fish on the line with the static drag on too tight can either break the line or even pull the entire fishing rig into the water. Conventional reels also use a so called palm drive braking mechanism that has the disadvantage that the fisherman's fingers are very near the winding handle as the reel spins out, and if the handle even momentarily strikes a finger, the sudden impulse resistance on the line can break the line or pull the hook. What is needed, especially in a fly reel, is a second or dual palm drag providing a rim for palm or thumb that is on the opposite side of the spool from the winding handle. This is generally not possible in conventional designs because the spool is highly enclosed to protect it and the exposed bearings from water and salt, and the second rim, even if available on the spool itself, is not available to the fisherman.
What is also needed, especially in a fly reel, is a dynamic, or live, drag mechanism that allows the fisherman to apply exactly the right amount of drag dynamically at all times, without removing his or her concentration from the fish, and without danger of sudden rush on the line causing line damage or loss of the fish.
Various attempts have also been made to deal with the problems of "backlash", few of which appear to have been widely accepted, most fisherman still preferring their thumbs for truly delicate casting without backlash. As is summarized well in U.S. Pat. No. 2,853,252 to Thiel, these attempts to prevent over running of the line by the spool when the spool speed at some point in the cast exceeds the line speed all involve some means of slowing the spool as the line tension decreases. Some operate with direct contact to the line, or constant spring induced frictional resistance to the spool, others employ sophisticated electronic sensors and integrated circuitry to detect and control spool speed. Some are prone to introducing unwanted friction on the line during the cast itself, thus reducing its distance. Others problematically apply the wrong amount of resistance at less than the optimal times for each cast. What is needed is an anti-backlash mechanism that applies very little frictional resistance at the most, and then only at the very end of the cast as the spool rpm's first begin to slow, and which therefore permits skilled fisherman to even cast off the rod without first laying out yards of line preparatory to making the cast.